One-way clutch built-in type rotation transmission device

ABSTRACT

Abrasion powder from the clutch retainer  28   a  is prevented from getting mixed into the grease used for lubricating the roller clutch  10 , and the grease is prevented from becoming exposed to high temperatures, and so degrading too quickly is prevented in the grease. Specifically, a retaining piece  33  is formed at one end of the clutch retainer  28   a  in the inner-diameter side portion thereof, and a retaining collar section  34  is formed around the inner peripheral surface of the other end of the clutch retainer  28   a . The inner ring  21  for the clutch is held from both sides in the axial direction between the fitting portion  35  at the tip end of the retaining piece  33  and the retaining collar section  34 . Consequently, displacement in the axial direction of the clutch retainer  28   a  is limited, so that the axially opposite end surfaces of the clutch retainer  28   a  is prevented from coming in sliding contact with the sections that rotate relative to the clutch retainer  28   a , specifically the inside surfaces of a pair of collar sections  27   a   , 27   b  of the outer ring  25  for the clutch.

FIELD OF THE INVENTION

[0001] This invention relates to an improvement of a rotationtransmission apparatus of the built-in one-way clutch type.

BACKGROUND OF THE INVENTION

[0002] Rotation transmissions of the built-in one-way clutch type havebeen used for example as a follower pulley that is fastened to the endof the rotating shaft of the alternator that is an automobile generator,or as the pinion etc. that is fastened to an end of the rotating shaftof the starter motor in the starting apparatus of an automobile, or havebeen used for transmitting rotation to auxiliary devices from a separatedrive apparatus (motor) during idling stop while the engine is stopped.

[0003] An alternator is used for generating the necessary electricalpower for an automobile, the drive source of which is the engine of theautomobile. The construction of this kind of alternator has beendisclosed for example in Japanese Patent Publication No. Toku Kai Hei7-139550. FIG. 13 shows the alternator 1 that is described in thispublication. The rotating shaft 3 is supported inside the housing 2 by apair of rolling bearings 4 such that it rotates freely. In the middlesection of this rotating shaft 3 there is a rotor 5 and a commutator 6.Also, a follower pulley 7 is fastened on one end of this rotating shaft3 (right end in FIG. 13) in the section that protrudes out from thehousing 2. When installed in an engine, an endless belt runs around thisfollower pulley 7 such that the engine can rotate and drive the rotatingshaft 3 through the crankshaft.

[0004] Conventionally, a typical follower pulley 7 that was simplyfastened to the rotating shaft 3 was used. However, in recent years, arotation transmission apparatus with built-in one-way clutch has beenproposed and has been used somewhat. For example, in a pulley apparatuswith built-in one-way clutch, when the running speed of the endless beltis constant or when it is accelerating, power is transmitted from theendless belt to the rotating shaft, and when the running speed of theendless belt is decelerating, there is relative rotation between thefollower pulley and the rotating shaft. A pulley apparatus with built-inone-way clutch having this kind of function has been disclosed forexample in Japanese Patent Publications Nos. Toku Kai Sho 56-101353,Toku Kai Hei 7-317807, Toku Kai Hei 8-61443, Toku Kai Hei 8-226462, TokuKo Hei 7-72585, and French Patent Publication No. FR2726059A1.

[0005] FIGS. 14 to 16 show one example of a prior art pulley apparatuswith built-in one-way clutch as described in these publications. Thispulley apparatus with built-in one-way clutch has an inner-diameter-sidemember, specifically a sleeve 8, that is fitted over the rotating shaft3 of the alternator 1 (see FIG. 13). Also, there is a cylindricalouter-diameter-side member, specifically follower pulley 7 a, that islocated around this sleeve 8 such that it is concentric with the sleeve8. In addition, there is a pair of support bearings 9 and a rollerclutch 10, which is the one-way clutch, located between the outerperipheral surface of the sleeve 8 and the inner peripheral surface ofthe follower pulley 7 a.

[0006] The sleeve 8 has a generally cylindrical shape, and is fittedonto one end of the rotating shaft 3 of the alternator 1 such that itrotates freely with the rotating shaft 3. Therefore, in the exampleshown in the figure, there is a male screw section formed around theouter peripheral surface on the tip end of the rotating shaft 3, and ascrew hole 11 is formed in the middle section around the innerperipheral surface of the sleeve 8, such that the screw hole 11 can bescrewed together with the male screw section. Moreover, an attachmenthole section 12, having a hexagonal cross section, is formed on the tipend (left end in FIG. 14) on the inner peripheral surface of the sleeve8 such that the tip end of a tool such as a hexagonal wrench can beattached to this attachment hole section 12. Furthermore, the base endon the inner peripheral surface of the sleeve 8 (right end in FIG. 14)is a circular hole section 13 that can be fitted over the tip end of therotating shaft 3 at a portion closer to the middle of it such that thereis no play between them.

[0007] Construction of assembling the sleeve 8 and the rotating shaft 3such that they do not rotate relative to each other can be accomplishedas well using other construction such as a spline joint, non-circularfit, key joint, or the like. Also, the center section of the outerperipheral surface of the sleeve 8 is a large-diameter section 14 thathas a diameter that is larger than the other sections.

[0008] On the other hand, the tip end half on the outer peripheralsurface of the follower pulley 7 a is formed with a wave shaped crosssection along the width direction such that part of an endless belt,called a poly V-belt, can be placed around it. Also, the aforementionedroller clutch 10 is placed in the middle in the axial direction in thespace between the outer peripheral surface of the sleeve 8 and the innerperipheral surface of the follower pulley 7 a, and support bearings 9are placed on both ends in the axial direction of this space such thatthey are located on both sides in the axial direction of the rollerclutch 10, respectively.

[0009] Of these, the support bearings 9 support the radial load that isapplied to the follower pulley 7 a, and make it possible for thefollower pulley 7 a to rotate relative to the sleeve 8. In the exampleshown in the figures, ball bearings of the deep-groove type are used asthe support bearings 9. In other words, each of these support bearings 9comprises an outer race 16 that has an outer-ring raceway 15 of thedeep-groove type formed around its inner peripheral surface, an innerrace 18 that has an inner-ring raceway 17 of the deep-groove type formedaround its outer peripheral surface, and a plurality of balls 19 thatare located between the outer-ring raceway 15 and inner-ring raceway 17such that they rotate freely.

[0010] Also, the outer race 16 is fitted into and fixed around the innerperipheral surface near both ends of the follower pulley 7 a, and theinner race 18 is fitted onto and fixed around the outer peripheralsurface near both ends of the sleeve 8. In addition, in this state, onesurface in the axial direction of the inner races 18 comes in contactwith one of the axially opposite end surfaces (stepped surface) of thelarge-diameter section 14, respectively.

[0011] Moreover, in the example shown in the figures, by placing sealrings 20 between the inner peripheral surface on the opposite ends ofthe inner races 16 and the outer peripheral surface on the opposite endsof the inner races 18, respectively, the openings on both ends of thespaces where the balls 19 are located are covered.

[0012] Also, of the openings on both ends of the spaces where the balls19 are located, it is possible to place the seal rings 20 only at theopenings on the sides of the outside spaces of the pulley apparatus.However, as in the example shown in the figure, in the case where theseal rings 20 are placed also at the openings on the sides of the insidespaces of the pulley apparatus, it is preferred that through-holes beformed through part of the seal rings 20 on the sides of these insidespaces in order that the space between the pair of support bearings 9 iscommunicated with the spaces where the balls 19 are located. The reasonfor this is that it prevents the pressure in the space between bothsupport bearings 9 from rising excessively when pressing the supportbearings 9 between the inner peripheral surface of the follower pulley 7a and the outer peripheral surface of the sleeve 8.

[0013] Also, the aforementioned roller clutch 10 transmits rotationforce between the follower pulley 7 a and the sleeve 8 only when thepulley 7 a rotates in relation to the sleeve 8 in a specified direction.In order to form this kind of roller clutch 10, an inner ring 21 for theclutch is securely fastened around the large-diameter section 14 of thesleeve 8 through interference fit.

[0014] In this specification, the outer peripheral surface of the sleeve8 will be called “one peripheral surface”, and the inner ring 21 for theclutch will be called the “protruding section”.

[0015] This inner ring 21 for the clutch is made from steel plate, suchas carburized steel plate, and is formed into a generally cylindricalshape by using a plastic working process such as pressing, and a camsurface 22 is formed on its outer peripheral surface. In other words, aplurality of concave sections 23, called the ramp section, are formed atequally space intervals around the circumference on the outer peripheralsurface of the inner ring 21 for the clutch, to form a cam surface 22 onthe outer peripheral surface. This cam surface 22 can also be formeddirectly on the outer peripheral surface of the large-diameter section14. In this specification, this large-diameter section 14 will be calledthe “protruding section”.

[0016] Of the inner peripheral surface of the outer ring 25 for theclutch, which is securely fitted into and fastened through interferencefit in the middle section of the inner peripheral surface of thefollower pulley 7 a, at least the middle section in the axial directionthat comes in contact with the rollers 26 (described later) is a simplecylindrical section. This kind of outer ring 25 for the clutch is alsomade from steel plate, such as carburized steel plate, and is formedinto a generally cylindrical shape by using a plastic working processsuch as pressing, and inward facing flange-shaped collar sections 27 a,27 b are formed on the axially opposite ends, respectively.

[0017] With respect to these collar sections 27 a, 27 b, the collarsection 27 a (left collar section in FIG. 14) is formed in advance whenmanufacturing the outer ring 25 for the clutch, so its materialthickness is the same as the thickness of the cylindrical section of theouter ring 25 for the clutch. On the other hand, the other collarsection 27 b (right collar section in FIG. 14) is formed on the insidein the radial direction of the outer ring 25 for the clutch after therollers 26 and the clutch retainer 28 (described later) are assembled,and therefore made thin.

[0018] Also, the plurality of rollers 26, which together with the innerring 21 and outer ring 25 for the clutch make up the roller clutch 10,are supported in the clutch retainer 28, which is fitted around theinner ring 21 for the clutch and can not rotate with respect to theinner ring 21 for the clutch, such that they can freely rotate anddisplace a little in the circumferential direction. This clutch retainer28 is made of a synthetic resin (for example, a synthetic resin such aspolyamide 66, polyamide 46, or polyphenylene sulfide in which glassfibers are mixed by an amount of about 20%) formed into a generallybasket-shaped cylindrical shape and comprises a pair of ring-shaped rims29, and a plurality of columns 30 that link the rims 29 with each other.

[0019] Also, pockets 31 are defined by the inside surfaces of the rimsections 29 and the side surfaces in the circumferential direction ofthe columns 30. The pockets 31 hold the rollers 26 such that they canfreely roll and slightly displace in the circumferential direction.

[0020] Moreover, the circular arc-shaped convex sections 32 are formedat a plurality of locations on the inner peripheral surface of each ofthe rim sections 29 and engaged with the concave sections 23 that areformed on the outer peripheral surface of the inner ring 21 for theclutch, so that the clutch retainer 28 is mounted on the inner ring 21for the clutch such that it cannot rotate relative to the inner ring 21for the clutch.

[0021] Also, there are springs (not shown in the figure), such as platesprings or synthetic resin springs, which are integrated with the clutchretainer 28 and located between the column sections 30 of the clutchretainer 28 and the rollers 26. There is a cylindrical-shaped spacebetween the cam surface 22 and the inner peripheral surface (cylindricalsurface) in the middle section of the outer ring 25 for the clutch. Theaforementioned springs elastically press the rollers 26 in thecircumferential direction of the clutch retainer 28 toward the sectionof the cylindrical-shaped space where the dimension of the width in theradial direction is narrower.

[0022] Moreover, the both axial end surfaces of the clutch retainer 28closely face the inside surfaces of the collars 27 a, 27 b of the outerring 25 for the clutch to prevent the clutch retainer 28 fromdisplacement in the axial direction.

[0023] When using the pulley apparatus with built-in one-way clutch thatis constructed as described above, the rollers 26 bite into the sectionwhere the width in the radial direction of the cylindrical-shaped spaceis narrower when the follower pulley 7 a rotates in a specifieddirection relative to the sleeve 8, which makes it impossible for thefollower pulley 7 a to rotate relative to the sleeve 8. This state iscalled the locked state.

[0024] On the other hand, when the follower pulley 7 a rotates in theopposite direction of the specified direction relative to the sleeve 8,the rollers 26 move out of the way to the section where the width in theradial direction of the cylindrical space is wider, and makes itpossible for the follower pulley 7 a to rotate freely relative to thesleeve 8. This state is called the overrun state.

[0025] There are the following two reasons for using a pulley apparatuswith built-in one-way clutch for an alternator that has the constructiondescribed above.

[0026] The first reason is for extending the life of the endless belt.For example, when the drive engine is a diesel engine, and it isrotating at a low rpm such as during idling, fluctuation in therotational angular velocity of the crankshaft becomes large. As aresult, the running speed of the endless belt that extends around thedrive pulley also fluctuates small. On the other hand, the rotatingshaft 3 of the alternator that is rotated and driven by this endlessbelt by way of the follower pulley does not fluctuate so suddenly due tothe inertia mass of the rotating shaft 3 and the rotor that is fixed tothe rotating shaft 3.

[0027] However, when the follower pulley is just fastened to therotating shaft, there is a tendency for the endless belt and followerpulley to rub in both directions due to the fluctuations in therotational angular velocity of the crankshaft. As a result, stress actsrepeatedly in different directions on the endless belt in a rubbingrelation with the follower pulley, and accordingly it becomes easy forslipping to occur between the endless belt and the follower pulley, orthe life of the endless belt becomes short.

[0028] Therefore, by using a pulley apparatus with built-in one-wayclutch for an alternator as this follower clutch, rotational power isfreely transmitted from the follower pulley to the rotating shaft 3 whenthe running speed of the endless belt is constant or increases, andconversely, the follower pulley rotates freely with respect to therotating shaft 3 when the running speed of the endless belt decreases.In other words, when the running speed of the endless belt decreases,the rotational angular velocity of the follower pulley becomes slowerthan the rotational angular velocity of the rotating shaft, and thusprevents strong rubbing at the area of contact between the endless beltand the follower pulley. In this way, the direction of the stress actingon the area of rubbing between the follower pulley and endless belt ismade constant, and thus prevents slipping from occurring between theendless belt and the follower pulley, and prevents a drop in life of theendless belt.

[0029] The second reason is for improving the efficiency of powergeneration of the alternator. The rotating shaft 3, to which thealternator rotor is fastened, is driven and rotated by the automobiledrive engine by way of the endless belt and follower pulley. In the caseof using a fixed follower pulley, when the rotational velocity of thedrive engine drops suddenly, there is a sudden drop in the rotationalvelocity of the rotor, and the amount of power generated by thealternator also decreases suddenly.

[0030] By using a pulley apparatus with built-in one-way clutch for analternator as the follower clutch of the alternator, the rotationalvelocity of the rotor drops gradually due to the inertial force andpower generation continues even when the rotational velocity of thedrive engine drops suddenly. As a result, in comparison to the case ofusing a fixed follower pulley, it is possible to increase the amount ofpower generated by the alternator by efficiently using the kineticenergy of the rotating shaft and rotor.

[0031] In the case of the prior art construction described above,displacement of the clutch retainer 28 in the axial direction isprevented by the pair of collar sections 27 a, 27 b that are formed onboth ends of the outer ring 25 for the clutch. In other words, when theclutch retainer 28 tries to move in the axial direction during overrunwhen there is relative rotation between the follower pulley 7 a and thesleeve 8, the inside surface of one of the collar sections 27 a, 27 bcomes in contact (sliding contact) with the corresponding end surface inthe axial direction of the clutch retainer 28, and prevents thedisplacement of clutch retainer 28 in the axial direction.

[0032] However, in the case of the pulley apparatus with built-inone-way clutch for an alternator described above, the relativerotational velocity between the pulley 7 a and the sleeve 8 can reachfrom several hundred revolutions per min (rpm) to several thousandrevolutions per minute in extreme cases. Therefore, when there issliding contact between the axially opposite end surfaces of the clutchretainer 28 and the inside surfaces of the collar sections 27 a, 27 b,respectively, there is a possibility of wear of the axially opposite endsurfaces of the clutch retainer 28, or there is a possibility that thefriction heat that occurs due to sliding contact between the axiallyopposite end surfaces of the clutch retainer 28 and the inside surfacesof the collar sections 27 a, 27 b may become excessive.

[0033] Also, in the case that the powder generated due to wear of theaxially opposite end surfaces of the clutch retainer 28 is mixed withthe grease used for lubricating the roller clutch 10, there is apossibility that there will be a drop in the lubricating ability of thisgrease. Moreover, in the case that the friction heat, which is generatedin the area of sliding contact, becomes excessive, there is apossibility that the grease will degrade quickly due to heat.Degradation of the grease causes the roller clutch 10 to lose durabilityand is not desirable.

[0034] These kinds of problems also occur in the case of constructionwhere there is not a pair of collar sections 27 a, 27 b, and where theaxially opposite end surfaces of the clutch retainer 28 come in slidingcontact with another member that rotates relative to the clutch retainer28.

[0035] Moreover, in the case of the clutch retainer that is disclosed inJapanese patent publication No. Toku Kai 2001-32911, which was assignedto the same assignee as the present invention, there are attachmentsections on both sides in the axial direction of the clutch retainer,and when the clutch retainer is elastically deformed and fitted onto theinner ring for the roller clutch, the aforementioned attachment sectionshold the inner ring for the roller clutch between them and limitdisplacement in the axial direction of the clutch retainer.

[0036] However, depending on the material of the retainer and theinterference between the attachment sections and the inner ring for theroller clutch, there existed problems in that when elastically deformingthe clutch retainer and fitting it onto the inner ring for the rollerclutch, the retainer could break, or the interference would be toolarge, so that the fitting force would be too large making fittingdifficult, or the interference would be too small, so that the clutchretainer would become separated easily.

Disclosure of the Invention

[0037] The rotation transmission apparatus with built-in one-way clutchof this invention is invented to solve the aforementioned problems.

[0038] Similar to the prior art construction shown in FIGS. 14 to 16,the rotation transmission apparatus with built-in one-way clutch of thisinvention comprises: an inner-diameter-side member that is fastened toan end of the rotating shaft; a cylindrical-shaped outer-diameter-sidemember that is located around the inner-diameter-side member such thatit is concentric with the inner-diameter-side member; a one-way clutchthat is located between the middle section in the axial direction of theouter peripheral surface of the inner-diameter-side member and themiddle section in the axial direction of the inner peripheral surface ofthe outer-diameter-side member; and a pair of support bearings that arelocated on both sides in the axial direction of the one-way clutchbetween the outer peripheral surface of the inner-diameter-side memberand the inner peripheral surface of the outer-diameter-side member. Theone-way clutch freely transmits rotational power between theouter-diameter-side member and the inner-diameter-side member only whenthe outer-diameter-side member rotates relative to theinner-diameter-side member in a specified direction. The pair of supportbearings support the radial load that is applied to theouter-diameter-side member, while at the same time making it possiblefor relative rotation between the inner-diameter-side member and theouter-diameter-side member.

[0039] Also, a protruding section is formed all the way around one ofthe inner peripheral surface of the outer-diameter-side member and theouter peripheral surface of the inner-diameter-side member at theaxially middle section thereof such that it protrudes in the radialdirection from that peripheral surface. Part of the one peripheralsurface that includes the peripheral surface of the protruding sectionis engaged with part of the peripheral surface of the clutch retainer ofthe one-way clutch in an interlocking manner, so that the clutchretainer is capable of rotating freely together with the member with theprotruding section.

[0040] Furthermore, retaining sections are formed on both ends in theaxial direction of the clutch retainer, in the sections that protrudefurther in the axial direction than the axially opposite end edges ofthe protruding section, such that they protrude toward the oneperipheral surface, and these retaining sections hold the protrudingsection between them on both sides in the axial direction so as to limitdisplacement in the axial direction of the clutch retainer and toprevent the axially opposite end surfaces of the clutch retainer fromcoming in contact with members rotating relative to the clutch retainer.

[0041] Furthermore, one feature of the rotation transmission apparatuswith built-in one-way clutch of this invention is that the clutchretainer is made of a material of synthetic resin with reinforcementfibers mixed in such that the percentage of the mixed-in reinforcementfibers is 25% or less.

[0042] As described above, in the case of the rotation transmissionapparatus with built-in one-way clutch of this invention, the clutchretainer can sufficiently deform elastically, so the clutch retainerwill not break when inserting it in the inner ring for the rollerclutch.

[0043] Furthermore, another feature of the pulley apparatus withbuilt-in one-way clutch of this invention is that the one peripheralsurface is the outer peripheral surface of the inner-diameter-sidemember, and the outer ring for the clutch is fitted inside the middlesection in the axial direction of the outer-diameter-side member and hasa pair of ring sections on both ends in the axial direction that extendinward in the radial direction such that the inside surfaces of the ringsections that face each other come very close to and face the axiallyopposite end of the clutch retainer, respectively.

[0044] In the case of the construction of the other feature, there isalways a clearance between the inside surfaces of the pair of ringsections which are formed on both ends in the axial direction of theouter ring for the clutch, and the axially opposite end surfaces of theclutch retainer. Therefore, this clearance is used as a grease pocket inorder that the one-way clutch is sufficiently lubricated. In otherwords, when using the rotation transmission apparatus with built-inone-way clutch, centrifugal force is applied on the grease in thisclearance. Also, the grease that receives the centrifugal force in thisway spreads evenly over the inner peripheral surface of the outer ringfor the clutch. As a result, it is possible to adequately supply greaseto the area between the surface of the locked members of the one-wayclutch and the inner peripheral surface of the outer ring for theclutch, which is the area that requires grease during overrun.Therefore, it is possible to maintain a state of lubrication of theclutch over a long period of time, as well as it is possible to obtain arotation transmission apparatus with built-in one-way clutch withsufficient durability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0045]FIG. 1 is a cross sectional view of a half of a first example ofthe embodiment of the present invention.

[0046]FIG. 2 is an enlarged view of Portion II in FIG. 1 to show aretainer for clutch, roller and an inner ring for clutch only.

[0047]FIG. 3 is a view in the direction III in FIG. 2.

[0048]FIG. 4 is a view in the direction IV in FIG. 2.

[0049]FIG. 5 is a view similar to FIG. 3 to show a second example of theembodiment of the present invention.

[0050]FIG. 6 is a cross sectional view taken along the line VI-VI inFIG. 5.

[0051]FIG. 7 is a cross sectional view of a half of a third example ofthe embodiment of the present invention.

[0052]FIG. 8 is a view similar to FIG. 3 to show the third example ofthe embodiment of the present invention.

[0053]FIG. 9 is a view in the direction IX in FIG. 8.

[0054]FIG. 10 is a cross sectional view of a half of a fourth example ofthe embodiment of the present invention.

[0055]FIG. 11 is a view similar to FIG. 3 to show the fourth example ofthe embodiment of the present invention.

[0056]FIG. 12 is a view in the direction XII in FIG. 11.

[0057]FIG. 13 is a cross sectional view to show an example of theconventional alternator.

[0058]FIG. 14 is a cross sectional view to show a half of an example ofthe conventional structure.

[0059]FIG. 15 is a perspective view of part of an inner ring for clutchtaken from the outer diameter side.

[0060]FIG. 16 is a perspective view of part of a retainer for clutchtaken from the inner diameter side.

THE BEST EMBODIMENT TO WORK THE INVENTION

[0061] The embodiment of the invention will be explained with referenceto the accompanying drawings.

[0062] FIGS. 1 to 4 show a first example of the embodiment of theinvention. A feature of this invention is that the displacement in theaxial direction of the clutch retainer 28 a is limited, so that it ispossible to prevent contact (sliding contact) between the axiallyopposite end surfaces of the clutch retainer 28 a and the insidesurfaces of the pair of collar sections (ring sections) 27 a, 27 b ofthe outer ring 25 for the clutch. The construction and function of otherparts, including that the clutch retainer 28 a rotates freely togetherwith the inner ring 21 for the clutch based on the engagement betweenthe plurality of convex sections 32 that are formed on the innerperipheral surface of the clutch retainer 28 a and the plurality ofconcave sections 23 that are formed on the outer peripheral surface ofthe inner ring 21 for the clutch, are substantially the same as in theprior art construction described above and shown in FIGS. 14 to 16.Therefore, the like code numbers will be given to like parts, andexplanations of redundant parts will be omitted or simplified. Theexplanation below will center on the features of this invention.

[0063] In the case of this example, the dimension L_(28a) in the axialdirection of the clutch retainer 28 a is greater than the dimension L₂₁in the axial direction of the inner ring 21 for the clutch(L_(28a)>L₂₁). Also, a first retaining section, specifically retainingpiece 33 is formed on the inner-diameter-side on one end (right end inFIGS. 1 and 2) in the axial direction of the clutch retainer 28 a, and asecond retaining section, specifically retaining collar section 34 isformed on the inner peripheral surface on the other end in the axialdirection (left end in FIGS. 1 and 2). The inner ring 21 for the clutchis held on both sides in the axial direction between and by theengagement section 35, which is formed on the tip end of the retainingpiece 33, and the retaining collar section 34.

[0064] The retaining piece 33 is located at one location or a pluralityof locations around the circumference on the inner-diameter side of theone end of the clutch retainer 28 a, as shown in detail in FIG. 3. Inother words, in order to form this retaining piece 33, a relief groove36 is formed between adjacent convex sections 32 in the circumferentialdirection on the inner peripheral surface of one end of the clutchretainer 28 a such that it is open in the inner peripheral surface ofthe clutch retainer 28 a and in the surface on the one end. Also, theretaining piece 33 is formed such that it protrudes in the axialdirection from the middle section of the inner-diameter-side of theaxially inside surface 37 of the relief groove 36. An engagement section35 is provided on the inner peripheral surface of the tip end of theretaining piece 33 such that it protrudes inwards in the radialdirection. The engagement section 35 in a free state protrudes radiallyinwards than the inner peripheral surface of the clutch retainer 28 a.

[0065] Also, there is an inclined section 38 formed on one end of theinner peripheral surface of the engagement section 35 such that itslants outward in the radial direction as it gets near the one end edge.

[0066] The depth D₃₆ of the relief groove 36 in the radial direction ofthe clutch retainer 28 a is large enough that the engagement section 35of the retaining piece 33 can be moved out of the way inside the reliefgroove 36 so that the clutch retainer 28 a can be pressed against theouter peripheral surface of the inner ring 21 for the clutch whenassembling the clutch retainer 28 a as described later. For example, thedepth D₃₆ of the relief groove 36 is equal to or greater than thethickness T₃₃ of the tip end of the retaining piece 33 (D₃₆≧T₃₃).

[0067] Moreover, the retaining collar 34 protrudes inward in the radialdirection from the inner peripheral surface on the other end of theclutch retainer 28 a, and is formed all the way around or intermittentlyaround the circumference. Also, in a section of the retaining collar 34which is aligned with the retaining piece 33 in the circumferentialdirection, there is a notch 39 that has a width dimension W₃₉ that isequal to or greater than the width dimension W₃₅ of the engagementsection 35 of the retaining piece 33 (W₃₉≧W₃₅). This notch 39 is formedso that when making the clutch retainer 28 out of synthetic resin byinjection molding (the retaining piece 33 is formed by axial drawing),it is possible to remove in the axial direction part of the mold that isused for injection molding.

[0068] The plurality of convex sections 32 are formed on the innerperipheral surface of the clutch retainer 28 a, and the plurality ofconcave sections 32 are formed on the outer peripheral surface of theinner ring 21 for the clutch.

[0069] In the case of mounting the clutch retainer 28 a mentioned aboveon the outer peripheral surface of the inner ring 21 for the clutch, thephase in the circumferential direction of the plurality of convexsections 32 and the plurality of concave sections 23 matches. Also, inthis state, the clutch retainer 28 a is pushed against the outerperipheral surface of the inner ring 21 for the clutch from the side ofthe other end (left end side in FIGS. 1 and 2) of the inner ring 21 forthe clutch. As the inclined surface 38 that is formed on the engagementsection 35 of the retaining piece 33 is guided by the outer peripheraledge on the other end of the inner ring 21 for the clutch, when pushingthe clutch retainer 28 a, the tip end of the retaining piece 33 iselastically deformed outward in the radial direction.

[0070] The angle α of the inclined surface of the engagement sectionwith respect to the axis should be 35 degrees or less. When the angle ismade large, the insertion load becomes extremely large, and insertionbecomes difficult to perform by hand. On the other hand, when the angleis small, insertion is easy, however, in order for the inclined surfaceto securely come in contact with the outer peripheral edge of the innerring for the clutch during insertion, the width of the engagementsection of the retainer must be made large due to the interference, andthus the space in the axial direction becomes large. Therefore, it isnot practical to make the angle α extremely small. It is preferred thatthis angle α be between 25 to 35 degrees.

[0071] Taking the expansion of the retainer and the inner ring for theclutch at maximum temperature during operation (approximately 110 to140° C.), interference in the radial direction between the engagementsection of the retainer and the inner ring for the clutch should be setso that no gaps occur.

[0072] In order to make it easy to insert the clutch retainer in theinner ring for the clutch, and in order that the engagement section doesnot come out after insertion, the direction of the outer diameter shapeof the inner ring for the clutch is regulated. In other words, theinsertion side is the side where there is large roll-over of the outerdiameter shape of the inner ring for the clutch, and the side oppositefrom the insertion side is the side where there is little roll-over ofthe outer diameter shape of the inner ring for the clutch. When theinner ring for the clutch is manufactured by pressing, the insertionside is the roll-over side (curl side during pressing) and the sideopposite from the insertion side is the side with little roll-over(bottom side during pressing).

[0073] Due to this elastic deformation, the engagement section 35 movesout of the way inside the relief groove 36 and passes by the outerperipheral surface of the inner ring 21 for the clutch. Also, after ithas passed by the outer peripheral surface of the inner ring 21 for theclutch, the tip end of the retaining piece 33 elastically restores indimension inward in the radial direction, and the inner ring 21 for theclutch is held in the axial direction between the engagement section 35and the retaining collar 34.

[0074] Moreover, in the case of this example, axial displacement of theclutch retainer 28 a is restricted by holding the inner ring 21 for theclutch between the engagement section 35 and the retaining collarsection 34 in the axial direction. The outer ring 25 for the clutchrotates relative to the clutch retainer 28 a. Also, by restricting theclutch retainer 28 a as described above, the axially opposite endsurfaces of the clutch retainer 28 a can be prevented from coming incontact with the inside surfaces of the pair of collar sections 27 a, 27b that are formed on the axially opposite ends of the outer ring 25 forthe clutch. In other words, in this embodiment, the dimensions are suchthat when there is a tendency for the clutch retainer 28 a to move inthe axial direction, either the engagement section 35 or retainingcollar 34 comes in contact with the corresponding end surface in theaxial direction of the inner ring 21 for the clutch before either one ofthe end surfaces in the axial direction of the clutch retainer 28 acomes in contact with the corresponding inside surface of one of thecollar sections 27 a, 27 b.

[0075] As described above, in the case of the pulley apparatus withbuilt-in one-way clutch of this invention, it is possible to prevent theopposite end surfaces of the clutch retainer 28 a from coming in contact(sliding contact) with the inside surfaces of the pair of collarsections 27 a, 27 b that rotate relative to the clutch retainer 28 a.Moreover, there is no wear on either of the end surfaces in axialdirection of the clutch retainer 28 a, nor is friction heat generated inthe area of both ends surfaces in the axial direction of the clutchretainer 28 a. Therefore, it is possible to prevent abrasion powder fromthe clutch retainer 28 a from getting mixed into the grease used forlubricating the roller clutch 10, and thus it is possible to prevent thegrease from becoming exposed to high temperatures and degrading tooquickly.

[0076] Furthermore, in this embodiment, there is always a clearancebetween the inside surfaces of the pair of collar sections 27 a, 27 band both end surfaces in the axial direction of the clutch retainer 28a. Therefore, this clearance is used as a grease pocket, making itpossible to adequately lubricate the roller clutch 10. In other words,when the pulley apparatus with built-in one-way clutch is operating,centrifugal force acts on the grease that is in this clearance. Thegrease that is subject to this centrifugal force uniformly spreads overthe inner peripheral surface of the outer ring 25 for the clutch. As aresult, during overrun when there is relative rotation between thefollower pulley 7 a and the sleeve 8, it is possible to adequatelysupply grease to the parts that require grease, or in other words,between the rolling contact surfaces of the plurality of rollers 26 ofthe roller clutch 10 and the inner peripheral surface of the outer ring25 for the clutch. Therefore, it is possible to maintain a good state oflubrication in the roller clutch 10 over a long period of time, andobtain a pulley apparatus with built-in one-way clutch that issufficiently durable.

[0077] The clutch retainer is made of synthetic resin (for examplepolyamide 66, polyamide 46, or polyphenylene sulfide in which glassfibers are mixed in). However, for construction such as in this examplewhere the engagement section is elastically deformed in the radialdirection and inserted in the inner ring for the clutch, the materialmust be such that the engagement section does not break when deformed.When the amount of glass fibers that are mixed in is increased, itbecomes easier for the engagement section to break when the specifieddeformation is applied, so it is necessary to restrict the amount ofglass fibers that are mixed in. From the tests performed by theinventors, it was confirmed that if the amount of glass fibers that aremixed in is 25% or less, there is no breakage. It is preferred that themixing amount be 15% or less.

[0078] It is also possible to have construction with no relief groove inthe engagement section. In the case of construction with no reliefgroove, the entire retainer must be deformed and inserted. In order tomake it easy to deform, it is preferred that there be only a fewengagement sections. Preferably there should be engagement sections atone or two locations. In the case of two locations, by locating theengagement sections at nearly symmetric locations or at adjacentlocations around the circumference, it becomes easier to deform theretainer. In the case of three locations or more, deformation becomeseasy by placing the engagement sections at locations with uneven pitch.

[0079] Next, FIGS. 5 and 6 show a second example of the embodiment ofthe invention. In this example, the shape of the retaining piece 33 athat is formed on inner-diameter side of one end of the clutch retainer28 b is different than in the first example described above. In thisexample, in order to form this kind of retaining piece 33 a, arectangular through-hole 40 is formed in the section between a pair ofconvex sections 32 which are adjacent in the circumferential direction,such that the through-hole 40 is provided through part of the clutchretainer 28 b in the radial direction. Also, the edge of the base end ofthe retaining piece 33 a is connected to an inside surface portion onthe inner-diameter side on one end side of the through-hole 40. Thisretaining piece 33 a, in the free state, slants inward in the radialdirection as it goes toward the center in the axial direction of theclutch retainer 28 b.

[0080] In the case of this example, the clutch retainer 28 b, includingthe retaining piece 33 a and through-hole 40 section, is made by radialdraw injection molding. Therefore, in this example, it is not necessaryto form a notch in part of the retaining collar section 34 (see FIG. 1,2 and 4), which is otherwise formed on the inner peripheral surface onthe other end of the clutch retainer 28 b for making it possible toperform axial draw injection molding. In the case of this example,constructed as described above, the retaining piece 33 a passes by theouter peripheral surface of the inner ring 21 for the clutch whileelastically moving out of the way inside the through-holes 40, whenpushing the clutch retainer 28 b against the outer peripheral surface ofthe inner ring 21 for the clutch (see FIGS. 1 and 2). Also, after it haspassed by the outer peripheral surface of the inner ring 21 for theclutch, the retaining piece 33 a elastically restores in dimensioninward in the radial direction, and the inner ring 21 for the clutch isheld in the axial direction between the tip end of the retaining piece33 a and the retaining collar section 34. The other construction andfunctions are substantially the same as for the first example describedabove.

[0081] Next, FIGS. 7 to 9 show a third example of the invention. In thecase of this example, with respect to the plurality of convex sections32 that are formed around the inner peripheral surface of the rimsection 29 on one side (right side in FIG. 7) of the clutch retainer 28c, there is a retaining section, specifically semi-circular retainingplate section 41 formed on one end of at least one of the convexsections 32. The inner ring 21 for the clutch is held from the axiallyopposite sides between the part of these retaining plate sections 41that protrudes further inward in the radial direction than the convexsections 32 and the retaining collar section 34 that is formed on theinner peripheral surface on the other end of the clutch retainer 28 c.

[0082] When placing the clutch retainer 28 c around the outer peripheralsurface of the inner ring 21 for the clutch, as pushing the clutchretainer 28 c, the retaining plate section 41 elastically deforms oneend of the clutch retainer 28 c outward in the radial direction whilepassing over the outer peripheral surface of the inner ring 21 for theclutch. The other construction and functions are substantially the sameas for the first example described above.

[0083] It is preferred that the quotient of the interference in theradial direction between the diameter of the inscribed circle of thesupport plate section and the inner ring for the clutch divided by thediameter of the inscribed circle of the support plate section be between0.01 to 0.04.

[0084] Next, FIGS. 10 to 12 show a fourth example of the embodiment ofthe invention. In this example, there is a plurality of convex sections32 that are formed around the inner peripheral surface of the rimsection 29 on one side (right side in FIG. 10) of the clutch retainer 28d. Also, there are semi-circular protrusions (retaining sections) 42formed near one end of at least one of the convex sections 32 such thatthey protrude inward in the radial direction. Also, there is a retainingcollar section 34 that is formed around the inner peripheral surface ofthe other end of the clutch retainer 28 d. The inner ring 21 for theclutch is held from the axially opposite sides between these protrusions42 and the retaining collar section 34. The other construction andfunctions are substantially the same as for the third example describedabove.

[0085] In the embodiments described above, the case of using a rollerclutch as the one-way clutch was explained, however, substantially thesame effects can be obtained when this invention uses a one-way clutchof other conventional construction, such as a sprag clutch or camclutch.

[0086] When using a cam clutch, the peripheral surfaces that are engagedwith the cam are all cylindrical surfaces. Therefore, there is apossibility that none of the members of the cam clutch is fitted withany of the peripheral surfaces. In that case, a protruding sectionhaving a stepped surface is formed directly on the one peripheralsurface such that the stepped surface is placed between the oneperipheral surface and the axially opposite sides, to control theposition in the axial direction of the clutch retainer.

[0087] Moreover, the pair of support bearings are not limited to being apair of ball bearings, and substantially the same effect can be obtainedas well in the case of using a pair of roller bearings or in the case ofusing one ball bearing and one roller bearing.

[0088] Furthermore, in the embodiments described above, an example ofapplying the invention to the pulley of an alternator is given, however,the invention is not limited to that. For example, in the case of usingthe invention in the rotation transmission unit of a starter motor inthe starting apparatus of an automobile, a pinion gear is formed on theouter peripheral surface of the cylindrical-shaped outer-diameter-sidemember such that it freely meshes with a ring gear that is formed on theouter peripheral surface of the flywheel.

Industrial Application

[0089] The rotation transmission apparatus with built-in one-way clutchof this invention, is constructed and functions as described above, sothe clutch retainer deforms elastically enough that it does not breakwhen inserted into the inner ring for the clutch. Also, grease in thegrease pocket is supplied to the clutch by centrifugal force, so it ispossible to maintain a good lubrication condition for the clutch over along period of time, as well as improve the durability of the clutch.

What is claimed is:
 1. A rotation transmission apparatus with built-inone-way clutch comprising: an inner-diameter-side member that isfastened to the end of a rotating shaft; a cylindrical-shapedouter-diameter-side member that is located around theinner-diameter-side member such that it is concentric with theinner-diameter-side member; a one-way clutch that is located between themiddle in the axial direction of the outer peripheral surface of theinner-diameter-side member and the middle in the axial direction of theinner peripheral surface of the outer-diameter-side member; such thatthe one-way clutch freely transmits rotational power between theouter-diameter-side member and the inner-diameter-side member only whenthe outer-diameter-side member rotates relative to theinner-diameter-side member in a specified direction, and a pair ofsupport bearings that are located on the axially opposite sides of theone-way clutch between the outer peripheral surface of theinner-diameter-side member and the inner peripheral surface of theouter-diameter-side member, such that the pair of support bearingssupport the radial load that is applied to the outer-diameter-sidemember, while at the same time making it possible for relative rotationbetween the inner-diameter-side member and the outer-diameter-sidemember, wherein a protruding section is formed all the way around one ofthe inner peripheral surface of the outer-diameter-side member and theouter peripheral surface of the inner-diameter-side member at theaxially middle section thereof such that it protrudes in the radialdirection from that surface, and the one-way clutch has a clutchretainer, wherein part of the one peripheral surface that includes theperipheral surface of the protruding section is engaged with part of theperipheral surface of the clutch retainer in an interlocking manner, sothat the clutch retainer is capable of rotating together with the memberwith the protruding section, wherein retaining sections are formed inthe axially opposite end edges of the clutch retainer, in the sectionsthat protrude further in the axial direction than the axially oppositeend edges of the protruding section, such that they protrude toward theone peripheral surface, and that the retaining sections hold theprotruding section on the opposite sides in the axial direction so as tolimit displacement in the axial direction of the clutch retainer and toprevent the axially opposite end surfaces direction of the clutchretainer from coming in contact with members rotating relative to theclutch retainer, and wherein the clutch retainer is made of a syntheticresin material with reinforcement fibers mixed therein such that thepercentage of the mixed-in reinforcement fibers is 25% or less.
 2. Therotation transmission apparatus with built-in one-way clutch of claim 1,wherein the one peripheral surface is the outer peripheral surface ofthe inner-diameter-side member, and the outer ring for the clutch isfitted inside the axially middle section of the outer-diameter-sidemember and has a pair of ring sections in the axially opposite ends thatextend inward in the radial direction such that the inside surfaces ofthe ring sections that face each other come very close to and face theaxially opposite end surfaces of the clutch retainer, respectively.